Henry grafton



(No Model.)

H. GRAFTON. STEAM OR OTHER ENGINE.

No. 427,171. Patented May 6, 1890.

N. m M AM me noms paens cn., Pmvrwurun., wAsHmsmn. n. c.

UNITED STATES PATENT OFFICE.

HENRY GRAFTON, OF LONDON, ENGLAND.

STEAM 0R OTHER ENGINE.

SPECIFICATION forming part of Letters Patent No. 427,171, dated May 6, 1890.

Application filed February 13 1890. Serial No. 340,322. (No model.)

To a/ZZ whom it may concern.-

Be it known that I, HENRY GRAFTN, fOr-- .engines of the kind described in another application for Letters Patent of the United States, Serial No. 325,330, in which there are `two oppositely-moving pistons in the same cylinder, the one farthest from the crank-shaft being connected to the pair of side cranks by a cross-head attached to the piston and connecting-rods passing alongside the cylinder.

The object of this improvement is to insure that the strain shall always be equally divided between the two connecting rods without throwing side strain upon the piston, notwithstanding that the connecting-rod brasses may wear unequally. In order, therefore, that the piston shall be subjected to no unbalanced side strains, which in a high-speed engine running at, say, one thousand or more revolutions per minute would have serious consequences, the invention consists, essentially, in pivoting the cross-head centrally to the piston by a transverse axis intersecting the longitudinal axis of the cylinder, so as to permit of the cross-head adjusting itself,in case of need, to compensate for unequal wear of the connecting-rod brasses, the cross-head being fitted to work in guides which resist the side strains on the cross-head due to the varying Obliquity of the connecting-rods.

Reference is to be had to the accompanying drawings, forming part of this specification, wherein- Figure l is a vertical section of as much of the engine as is necessary to illustrate the improvement; and Fig. 2 is a plan of the crosshead, guides, and piston.

The same letters of reference indicate like parts in both gures.

The engine consists of two single-acting pistons A B, working in a cylinder C and both connected to the same crank-shaft, the piston A to a middle crank D by a connecting-rod E, and the piston B,with a pairof side cranks F, by a pair of connecting-rods G and a crosshead J, the cranks F F being placed in line with each other and as nearly as possible diametrically opposite the crank D consistently with the operation of one of the pistons (for example, the piston B) as the distributionvalve, as described in the specification of my vother application for Letters Patent of the United States aforesaid.

The connecting-rods G take onto journals near the ends of the cross-head J, whose extreme ends are slide-blocks working in guides j on the engine-framing, by which the whole of the side strain due to the variable obliquity of the connecting-rods G is resisted. The cross-head J is pivoted at the middle of its length on a transverse pin J mounted in a forked stem h, iixed centrally to the piston B, so that the axis of pin J intersects the longitudinal axis of Vthe cylinder, the crosshead having clearance laterallyin the forked stem b, so that none of the side strain due to the Obliquity of the connecting-rods G will be transferred to the piston. The cross-head J, although pivoted, has no motion on its pivot when the engine is working normally; but in case of unequal wear of the connecting-rod brasses the cross-head will be free to accommodate itself accordingly, so as to always insure the equal participation of the two connecting-rods G G in the strain without throwing any side strain whatever on the piston.

I do not here claim the following: an engine constructed and operating substantially as herein specified, and consisting, essentially, of two pistons working in the bore of the same cylinder, the one piston being adapted to act also as a distribution-valve wholly controlling both the admission and exhaust, as herein described, and the two pistons being coupled t0 cranks on the same crankshaft, placed at such an angular distance apart that the two pistons will move in the cylinder in opposite directions for the greater part of the revolution, and that the one piston will act both as a distribution-valve and piston, substantially as set forth; nor the herein-described engine, consisting, essentially, of two pistons working in the bore of the same cylinder, (and moving therein in oppo- IUC site directions for the greater part of the revolution,) the one piston acting'also as a distribution-valve Wholly controlling both the admission and exhaust, and the two pistons being coupled to cranks on the same crank-shaft, placed at such an angular distance apart as to cause the motion of the pis- Y tons to be as nearly. balanced as is compatible with the most effective pperation of the one piston both as a distribution-valve and piston, substantially as set forth; nor, in the herein-described engine having two pistons Working in the same cylinder and coupled to cranks on the same crank-shaft, placed at such an angular distance apart as to cause the pistons to nearly balanceeach other, and yet admit of the one piston acting as distribution- Valve to wholly control both the admission and exhaust, the combination of an all-round circumferential. row of ports in a trunk of the said piston with all-round circumferential rows of admission and exhaust ports formed in thecylinder, substantially as and for the purpose specied; nor, in the herein described engine having two pistons Working in the same cylinder, the combination, with the same crank -shaft, of the one piston coupled with a middle crank by a single' central connecting-rod of the other piston, coupled by means of connecting-rods passing alongside the cylinder with two side cranks placed at such an angular distance from the middle crank as to cause the pistons to as nearly balance each other as is compatible with the effective operation of the one piston as a distribution-valve wholly controlling the admission and exhaust; nor, in the herein-described engine having two pistons Working in the same cylinder and coupled to cranks on' the same crank-shaft, arranged as described, the combination,with a trunk-piston adaptedto act as a distribution-Valve wholly controlling both the admission and exhaust, as described, of the second piston'entering the trunk-piston when the pistons approach each other, but without coming into contact therewith, so as to avoid waste spaces or long passages on the valve-piston, for the reason that the subject-matter here disclaimed is embodied in a separate application for patent iiled by lne September 27, 1889, known as Serial No. 325,330.

Having now particularly described and ascertained the nature of the said invention and in what manner the same is to be performed, I declare that what I claim is- In an engine having two pistons working in the same cylinder and coupled, the one to a middle crank and the other to a pair of side cranks on the same crank-shaft, arranged as described, the combination, with the piston farthest from the crank-shaft and with its connecting-rods passing alongside the cylinder, of a cross-head pivoted centrally to the said piston bya transverse axis intersecting the axis of the cylindenand'of guides for the cross-head, whereby the side strain of the connecting-rods is resisted and the piston is subjected to no unbalanced side strains, as specified.

The foregoing specification of my improvementin steam and other engines signed by me this 31st day of January, 1890.

HENRY GRAFTON.

Witnesses:

WILMER M. HARRIS, Notary Public, 17 Gracechurch Street, Lonclon.

THOMAS LAKE, Of same place, his clerk. 

